I recently purchased this toy to use as an experiment in learning more about TurboCad and I've nearly finished modelling all the parts. see The Toy.jpg

The plastic parts were all measured using a digital caliper and their respective 3D calculations should for the most part be accurate. What is somewhat more problematic is the shapes in Plastic Parts1.jpg ('yellow arrows') where they're a little more difficult to accurately measure. I did try scanning into a pdf and then copying to an image but neither the scanned pdf or the image file were good enough quality(see Capture1.jpg)

So I tried using a tracing tool and the results were not much better. Where the tracing tool I even tried importing as a pdf into tcw, while the import & scaling was ok, it was the line thickness that then became the issue. Where say I wanted to draw a circle (see Plastic Parts1.jpg orange arrow) in 2D that would represent the outline, yet the imported pdf file displays these parts in thicker lines. Sure I know this is not a tcw problem, it's due to the scanned printer image then into pdf and then into tcw etc etc.

So I'm now downto the old method of trying to obtain reasonably close accuracy by locating each part onto a ruled grid of 5mm drafting paper and plot the major features of the remaining pieces and then measuring the final minor features with the caliper.

Question: But is there a better way?

Once I've drawn the final pieces I then will post the tcw file to the forum so that all can benefit from the final renders and results and hopefully learn in the process and I will document how I made each piece. No materials have been added to the images yet!

There's a weary old jargon term in CAD, "design intent". When the toy's assembled, you know where each part fits, its relationship to the parts that are attached to it and their place in the final assembly. There are some ruling dimensions, the wheelbase, the diameter of the axles and bearings, the thread for the neck of the bottle, but for nearly all of the others, the dimensions are relative to each other rather than absolute.

I've been involved with reverse engineering for a long time, ultimately you need to determine a resolution that you can live and work with, whether it's determined by the resolution of your measuring tools or by the means by which you'll produce the clone. For additive rapid prototyping and 3D printing, layer and filament thickness mean that these will usually be coarser than subtractive means, CNC milling for example. For the toy, the only way you'd get a resolution that makes a copy indistinguishable from the original is to use the parts as a master for a steel epoxy or electrolytically deposited nickel cobalt mold.

The short answer: I'd settle on centre-to-centre dimensions for the parts with circular features, face-to-face relationships for the parts that align to each other, get the angles between the faces to agree (bearing in mind that they were originally probably designed with sensible angular figures, whole degrees or down to .1 resolution rather than arbitrary increment angles) and be very satisfied with making them look as similar to the original as possible.

Scale modellers who show their finished miniatures in shows gripe about judges who reckon they know about every nuance of the full-size prototype, those judges are called "rivet counters" because there have been occasions when they've asserted that the number of rivets in an aircraft panel's edge is wrongly represented (maybe they have, or maybe that's apocryphal exaggeration, but you get the drift), and there are people who build the miniatures who claim that they've exaggerated curves because it "corrects viewpoint perspective distortion". People like that can drive you mad, you don't need to do it for them...

See the attached photo as this will clarify my small problem. How to accurately measure ( as possible ) the parts inside the photo.

What I'm thinking is that if I lay the objects to be modeled onto graph paper, that way I can scale the size in 2D. Then lay them of by rotating 90 degrees to get the major height aspects. That way I have a reference point as to the objects boundaries in both 2D then as rotated 90 degrees along it's horizontal line and then model the minor features later.

What I did years ago was to scan a 6 inch ruler and crop it down to just the ruler in my image editing program (PSP-X) and save it. I would then paste the ruler image on a separate layer in the scanned image to be measured. I could move the ruler around and zoom in closer when necessary.

John R, I did try a ruler against the object some time back but the fundamental problem is still apparent, where the scanned object's line detail is just too big. It's just as if someone drew the objects with a 2-3mm line thickness therefore I'm unable to get enough detail from the scanned image or via scanned to pdf file. ATM I still measuring digitally.

John R, I did try a ruler against the object some time back but the fundamental problem is still apparent, where the scanned object's line detail is just too big. It's just as if someone drew the objects with a 2-3mm line thickness therefore I'm unable to get enough detail from the scanned image or via scanned to pdf file. ATM I still measuring digitally.

John R, I did try a ruler against the object some time back but the fundamental problem is still apparent, where the scanned object's line detail is just too big. It's just as if someone drew the objects with a 2-3mm line thickness therefore I'm unable to get enough detail from the scanned image or via scanned to pdf file. ATM I still measuring digitally.

Wondering if I change the scan resolution may help?

Daz

I was scanning the actual plastic 'tree' part, not a manufacturers picture, then measuring. I would rather measure actual parts than a drawing of what it looks like.

Photos or scans of the parts can be traced along edges, sharp yes-or-no demarcations. Line drawings make you estimate the centre of the drawing's lines - and you don't know whether the part/assembly drawing is a manual trace of a photo or the CAD drawing of the mold cavities and runner.

Where scanning through a printer does produce reasonable results, the resulting pdf is not sufficiently high enough clarity to permit accurate detail for measuring line thickness, circle, arcs, widths etc re: what I'm trying to achieve.

Running the pdf or image through a tracing app just makes the job more difficult again as it quite often breaks the line and circles into small discrete pieces.

The scanned images do leave some aspects details just a little to difficult to solve, that's why I use the old method of just measuring using a digital caliper, protractor and ruler all by eye. Of course errors will creep in due to the nature of how I'm doing this, but what I thought would be suitable alternative can lead to more problems. The best method I can think of is to set the plastic part object on a bench and measure using a digital height guage for accurate 2D measurements assuming you can find flat surfaces and using a ruler and protractor for other measurements or by flipping 90 degrees.

In Turbocad I use a simple angle copy, it's just four lines that are set at 90 degrees to each other ( just like a point star but much larger ) and then when I have two sides of an object that are easily measured I use the protractor to get the angle and then add another line to the simple angle copy then position that object exactly where the lines need to be placed. Then draw the required line to make the angle. This does take the guessing out.

Murray your spot on, it's the scanned thickness that is the issue. I you compare my plastic parts1.jpg versus John R's Vollmer drawing the line weight/thickness is where the problems occur.

Another way of "3D scanning" is building a heightfield map. I half-sized your pic to make it effectively 150 dpi to make it less noisy and more compact and used a heightfield from pic tool in another app to make an .obj.

Clean up the mesh a little and pass sections through it, and you start to get something that looks workable.

I was in the workshop building a small set of real simple tools to accurately measure the height and other main features, but I fell over after seeing a snake in the back of the workshop. No he didn't bite me but I tripped and spraind=ed my ankle so bad it look like I've got a watermelon attached to my foot. So this is on the back burner until I get mobile again.

I was in the workshop building a small set of real simple tools to accurately measure the height and other main features, but I fell over after seeing a snake in the back of the workshop. No he didn't bite me but I tripped and spraind=ed my ankle so bad it look like I've got a watermelon attached to my foot. So this is on the back burner until I get mobile again.

I'll post the ideas for the tool tomorrow.

Thanks

Daz

Watched a documentary about Australia a couple of years ago. Learned that you have 180 species of snakes there and that 130 of those species are venomous.

Where I live, it's not uncommon at all to encounter a snake in the house (have lots of stories about that!), but the few bad ones stay outdoors.

These simple tools have bee designed to overcome the problems in gaining accurate measurements by hand. There are many different methods of measurement but accuracy is the goal here. Therefore I designed these tools to overcome the errors that would have crept into my drawings by just working with hand tools alone ( like a ruler, protractor, digital caliper, etc).

All Main & Internal parts can be made from aluminium ( I'm gunna try clear perspex 15mm thick, that way I can etch 0 to 90 lines at 1mm intervals ) 15mm thick. All other dimensions can be read from the drawing directly. The shapes are somewhat arbitrary, I guess whatever works, but I did design it for the small parts in mind that I needed to get the dimensions as close as possible. eg: hole to hole centres, use the round guide or the square ( if you want to to make it, which ever suits best ) to plot the geometry relative to two or more of hole centres, use the caliper to pick of obscure angles then plot them against a protractor or digital angle, the dimension pins are designed for the small plastic part holes, chrome guide pins move through a slotted arc to capture the relative dimensions of discrete points or vertices etc. I'm also using radius gauges in my workshop, not shown here.

How It's Designed to Work

The inner chrome piece can be flipped to gain extra work area, just flip 180 degrees and re bolt.Place the part to measured on the Main & Internal pieces ( just under the blue plastic part is a series of holes 4 - 6mm ) and fix with a small clamp or bit of blue tack of etc. The fixed end of the Measuring: Round Guide ( sitting on the threaded chrome bolt ) is rotated as needed, select the desired dimension pin ( 2 - 6mm dia ) into the free or rotating end of the Round guide and place it into position to measure the radius etc. When you've got the points fixed, tighten the screw then remove the guide to measure against a ruler or other digital device.

Finally the Measuring Caliper is a simple design and it's primary function is to measure an objects two or more discrete sides thereby obtaining all relative angles and combining the geometry data that can be recorded and later used in the drawing.

How I will Make it

Using a rotary table mounted on the bed of my milling machine, just using digital scales for fine placement of cutting tools.

Henry, the snake on my end was a black snake, they're venomous but not in the same league as the highly dangerous taipan. There are many sightings in our area, but most are sighted from the coastal areas and inland. I've seen then situp if you like by about 1/2 meter and survey the surounding area.

123D catch is available and supported, Daz. 123dapp.com/catch. This is a model that the app created from photos of a small Morris Minor diecast toy, my first attempt. Analytic surfaces (planes, cylindrical and conical surface segments) are easier to work with, but the app is great for establishing proportional relationships.